JP3920899B1 - Method for producing modified coal - Google Patents

Abstract

The present invention provides a method for producing modified coal with arbitrarily adjusted softening and melting characteristics.
An extraction step of mixing coal particles and a non-hydrogen donating solvent and extracting a soluble component of the coal particles into the non-hydrogen donating solvent, a part of the extraction residue after the extraction step and extraction And a solvent removal step of removing the solvent from the mixture with the liquid.
[Selection figure] None

Description

  The present invention relates to a method for producing modified coal used for coking coking coal and the like.

  High-quality caking coal is mainly used as a raw material for coke, but this caking coal is expensive and its output is limited. Therefore, a method using low-grade coal has been proposed. For example, it has been proposed that a coal component is heated and extracted from coal using a non-hydrogen-donating solvent and an extracted coal having an ash concentration of 0.1% by weight or less is used as a coke raw material (see, for example, Patent Document 1). ). By using such extracted coal as a blended coal raw material, the proportion of low-caking coal or non-caking coal in the blended coal can be increased.

By the way, in the manufacture of coke, there is a process in which blended coal composed of several types of raw material coal is heated to high temperature to be coke. In order to produce high-quality coke with high strength, it is necessary to optimize the softening and melting characteristics of the raw coal. For this reason, a suitable softening and melting coal is selected from the limited coal types, but the selected coal does not necessarily have the optimum softening and melting property. Against this background, a technology that can optimize the softening and melting characteristics of coal is required.
Japanese Patent Laid-Open No. 2005-120185

  In view of the above circumstances, an object of the present invention is to provide a method for producing reformed coal in which softening and melting characteristics are arbitrarily adjusted.

  The present invention includes an extraction step of mixing coal particles and a non-hydrogen donating solvent and extracting the soluble component of the coal into the solvent, a part of the extraction residue after the extraction step, and an extract. And a solvent removal step of removing the solvent from the mixture.

The present invention also includes an extraction step of mixing coal particles and a non-hydrogen donating solvent to extract the soluble component of the coal into the solvent, and separating the extraction residue and the extract after the extraction step. A solid-liquid separation step, a mixing step of mixing a part of the extraction residue separated in the solid-liquid separation step and the extract separated in the solid-liquid separation step, and removing the solvent of the mixture after the mixing step A solvent removal step,
It is a manufacturing method of the modified coal characterized by having. The extraction residue separated in the solid-liquid separation step in this method includes a solvent in which coal particles are concentrated.

  The present invention also includes an extraction step of mixing coal particles and a non-hydrogen donating solvent to extract the soluble component of the coal into the solvent, a part of the extraction residue after the extraction step, and an extract A method of producing modified coal, comprising: a mixture separation step of extracting a mixture of the solvent and a solvent removal step of removing a solvent of the mixture.

  Each said manufacturing method is suitable as a manufacturing method of the modified coal for cokes.

  In the method of the present invention, since the non-hydrogen-donating solvent is removed from the mixture of a part of the extraction residue and the extract, the amount of the extraction residue in the mixture can be changed as appropriate, such as softening and melting. It is possible to produce a modified coal whose characteristics are arbitrarily adjusted. In addition, the modified coal produced by the method of the present invention has a homogeneous distribution of its components and a homogeneous and stable quality.

  The present invention will be described below based on embodiments. The method for producing modified coal according to the present embodiment includes an extraction step of mixing coal and an extraction solvent, and extracting a coal component soluble in the extraction solvent (hereinafter, extracted coal) into the extraction solvent, and the extracted coal. In this method, a solvent removal step of sequentially removing the extraction solvent from a mixture of the extraction solvent (hereinafter referred to as an extraction liquid) and the coal after extraction (hereinafter referred to as an extraction residue) is performed. In the method of the present invention, the method for preparing a mixture comprising the extraction residue and the extract is not particularly limited.

  In the method according to the first embodiment, between the extraction step and the solvent removal step, a solid-liquid separation step for separating the extraction residue and the extract after the extraction step, and the extraction residue after the solid-liquid separation step And a mixing step of mixing a part with the extract.

  FIG. 1 is a block diagram of an apparatus used in the method according to the first embodiment of the present invention. Hereinafter, a description will be given with reference to FIG. The illustrated apparatus includes a solvent supply tank 1 that supplies an extraction solvent, a coal supply tank 2 that supplies coal, a slurry preparation tank 3 that receives supplies from the solvent supply tank 1 and the coal supply tank 2, and a slurry preparation. An extraction tank 4 that receives a mixture of the extraction solvent and coal prepared in the tank 3, a settling tank 5 that separates the mixture of the extraction tank 4 into an extract and an extraction residue-concentrated slurry, and a discharge from the lower part of the settling tank 5 An extraction residue receiver 6 for receiving the extracted residue concentration slurry, a residue solvent recovery device 8 for evaporating and separating the extraction solvent from the extraction residue concentration slurry in the extraction residue receiver 6, and an upper portion of the settling tank 5 The extract liquid receiver 7 that receives the extract liquid discharged from the liquid extractor and the extract liquid solvent recovery device 9 that evaporates and separates the solvent from the extract liquid of the extract liquid receiver 7 are provided. In this apparatus, an introduction pipe 10 a for introducing the extraction residue into the extraction liquid receiver 7 is provided between the extraction residue receiver 6 and the extraction residue solvent recovery apparatus 8. And this apparatus is suitably provided with a valve (not shown) that opens and closes appropriately.

  First, the extraction process will be described. In this step, coal and extraction solvent are supplied from the solvent supply tank 1 and coal supply tank 2 to the slurry preparation tank 3, and a mixture of coal and extraction solvent in the slurry preparation tank 3 is supplied to the extraction tank 4.

  As the extraction solvent supplied from the solvent supply tank 1 to the slurry preparation tank 3, a non-hydrogen donating solvent is used. Common aromatic compounds such as benzene, toluene, and xylene generally used as solvents have a low coal component extraction rate, and when the extraction temperature is set high, the pressure for the setting becomes high. In addition, when a polar solvent such as N-methylpyrrolidone or pyridine is used, the extraction rate of the coal component is high, but the solvent is strongly bonded to the coal and it is difficult to remove the solvent from the coal. Moreover, in the case of an aromatic compound having three or more rings such as anthracene, the boiling point is too high, making it difficult to separate the coal and the solvent. Furthermore, hydrogen donating solvents such as tetralin used in coal liquefaction methods solubilize or liquefy coal and show a high extraction rate. However, since the hydrogen in the solvent moves to coal molecules, the solvent is recovered. However, it cannot be reused immediately. For the above reasons, in this embodiment, a non-hydrogen donating solvent is used as the extraction solvent.

  The non-hydrogen-donating solvent includes a bicyclic aromatic solvent having a boiling point of about 200 to 250 ° C. obtained by a coal carbonization process or a catalytic cracking process of heavy petroleum oil, such as methylnaphthalene, A solvent mainly composed of one or more selected from naphthalene and tar gas oil is preferably used.

  The coal supplied from the coal supply tank 2 to the slurry preparation tank 3 may be either high-grade coal or low-grade coal, and is not limited. That is, anthracite, bituminous coal, subbituminous coal, lignite, and the like are applicable. In order to improve the extraction efficiency of the extracted coal and the uniform distribution of the extracted coal in the modified coal to be produced, the coal is suitably pulverized into particles of 5 mm or less.

  In the slurry preparation tank 3, the supplied coal and the extraction solvent are mixed, and the coal and the extraction solvent are made into a slurry mixture.

  In the extraction tank 4, the extracted coal is extracted from the coal into the extraction solvent at a predetermined extraction temperature. The extraction temperature at this time is preferably 300 to 420 ° C. When the temperature is lower than 300 ° C., it becomes insufficient to weaken the bonding force between the coal constituent molecules, and the extraction rate of the extracted coal is lowered. Even when the temperature is higher than 420 ° C., the recombination of radicals generated by the pyrolysis reaction of coal occurs, so that the extraction rate of the extracted coal is lowered. Note that the pressure is adjusted so that the solvent does not reach the boiling point even at the extraction temperature, and it is usually preferable to adjust the pressure in the range of 0.8 to 2.5 MPa. Further, extraction is performed in the presence of an inert gas (for example, nitrogen).

  Next, the solid-liquid separation process will be described.

  The solid-liquid separation process in the present embodiment is performed in the settling tank 5. This sedimentation tank 5 is based on the gravity sedimentation method, and here, the extraction residue and the extraction liquid that are insoluble in the extraction solvent in the extraction step are separated. At this time, the solvent temperature and pressure are preferably set to the same temperature and pressure range as in the extraction step.

  The extract discharged from the upper part of the settling tank 5 is introduced into the extract receiver 7. On the other hand, the extraction residue discharged from the lower part of the settling tank 5 is discharged to the extraction residue receiver 6 as a slurry in which the extraction residue is concentrated.

  As will be described later, a part of the extraction residue is used in the mixing step, but the remaining extraction residue is removed by the extraction residue solvent recovery device 8 by a method such as evaporation to dryness or spray drying. By doing so, it is recovered as a solid extraction residue. Further, the removed solvent may be used again as the extraction solvent.

  Next, the mixing process will be described.

  In the mixing step, in the present embodiment, a part of the extraction residue of the extraction residue receiver 6 is supplied to the extraction liquid receiver 7 through the introduction pipe 10a, and the extraction residue, the extraction liquid, Is mixed. In order to enhance the uniform distribution of the extracted coal in the modified coal, it is preferable to mix a slurry-like mixture of the extract and the extraction residue with the extract.

  Since the properties of the modified coal such as softening and melting properties vary depending on the amount of the extraction residue mixed, an arbitrary amount for obtaining the modified coal having the desired properties is mixed. Therefore, a part of the separated extraction residue is mixed. For example, it is good to mix so that the ratio of the extraction residue and extraction coal in reformed coal may become a ratio of extraction residue: extraction coal = 1: 0.1-10000. When modified coal is used for coke, it varies depending on the properties of the extracted residue and the extracted coal, but it is generally preferable to adjust the extracted residue: extracted coal = 1: 0.1 to 1000.

  Next, the solvent removal step will be described.

  The extraction solvent is removed after the mixing step. This removal is performed by introducing a mixture of the extraction residue and the extraction liquid from the extraction liquid receiver 7 into the extraction liquid solvent recovery device 9 and performing a distillation method, a spray drying method, or the like. When the extraction solvent is removed, modified coal is obtained. In addition, you may reuse as an extraction solvent of an extraction process by collect | recovering the removed extraction solvent.

  The modified coal obtained through the above steps is a modified coal having desired characteristics because the mixing ratio between the extraction residue and the extracted coal is controlled. Moreover, in this method, since an extraction residue ratio can be made arbitrarily, coal of various characteristics is obtained from a certain kind of coal. Furthermore, since the distribution of the extraction residue and the extracted coal in the modified coal tends to be uniform, it is possible to obtain a modified coal with uniform and stable quality in which localization of properties such as softening and melting properties is suppressed.

  Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a configuration diagram of an apparatus used in the method according to the second embodiment. The present embodiment is similar to the first embodiment described above, and only differences from the first embodiment will be described.

  In the second embodiment, as shown in FIG. 2, the introduction pipe 10 b provided between the extraction residue receiver 6 and the extraction residue solvent recovery device 8 is not the extraction solution receiver 7 but the extraction solution solvent. It is connected to the collection device 9. That is, in the second embodiment, the extraction residue is directly introduced into the extraction solvent recovery device 9 that removes the solvent. That is, the mixing of the extract and the extraction residue concentrated slurry and the evaporation of the solvent are simultaneously performed in the extract solvent recovery apparatus 9 at the same time.

  Although the present invention has been described based on the embodiments as described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in the embodiment described above, the solid-liquid separation step is performed using a sedimentation tank, but solid-liquid separation by filtration is naturally possible. Further, in the above embodiment, the extraction residue is mixed with the extract after passing through the extraction residue receiver from the settling tank, but any slurry can be discharged directly from an appropriate position of the settling tank. It is also possible to take out the extract mixed with the extraction residue. The extraction residue mixed with the extract in the mixing step may be the residue after the solvent is removed.

  Moreover, in the said embodiment, although it is supposed that preparation of the mixture of a part of extraction residue and an extraction liquid will be performed after isolate | separating an extraction residue, the extraction liquid containing a part of extraction residue after an extraction process is used. Extraction is also a preparation of the mixture.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented within a range that can meet the purpose described above and below. All of which are within the scope of the present invention.

  A slurry-like mixture was prepared in which the extraction solvent (methylnaphthalene) and pulverized bituminous coal (coal A) or lignite (coal B) were in a weight ratio of 80:20. Next, this slurry-like mixture was extracted for 1 hour under conditions of a temperature of 370 ° C. and a pressure of 2 MPa. And the gravity liquid settling tank was used, the extract was taken out from the upper part of the settling tank, and the slurry-like mixture which consists of an extract and an extraction residue was taken out from the lower part. Then, the ratio of the extract taken out from the upper part of the gravity sedimentation tank and the slurry-like mixture taken out from the lower part was changed, and the mixture was prepared. Next, the extraction solvent was removed by evaporation to dryness to obtain modified coal.

  The softening and melting characteristics of the obtained modified coal were evaluated by industrial analysis values (measured based on JIS M 8812) and Gieseler plastometer measurements (based on JIS M 8801). The results are shown in Table 1.

  From Table 1, it can be confirmed that the content of ash and volatile components changes depending on the content of the extraction residue, and the softening and melting characteristics such as the softening start temperature have changed. Moreover, it turns out that the effect changes with kinds of coal.

  Separately from the above industrial analysis values and Gieseller plastometer measurement, the modified coal was embedded in resin, the cross section was cut out and observed with a digital microscope. As a representative example, the observation result of Example 6 is shown in FIG. FIG. 3 is an enlarged photograph of a cross section of the modified coal taken at 750 magnifications.

  In FIG. 3, the black portion is the extracted charcoal portion, and the gray granular portion having a size of about several μm is the extraction residue. Thus, it can be seen that the fine particles of the extraction residue are uniformly dispersed inside the extracted coal.

It is a block diagram of the apparatus used with the method which concerns on 1st embodiment of this invention. It is a block diagram of the apparatus used with the method which concerns on 2nd embodiment of this invention. It is a cross-sectional photograph (750 magnifications) of the modified coal of Example 6.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solvent supply tank 2 Coal supply tank 3 Slurry preparation tank 4 Extraction tank 5 Sedimentation tank 6 Extraction residue receiver 7 Extraction liquid receiver 8 Extraction residue solvent recovery apparatus 9 Extraction solvent recovery apparatus 10a, 10b Introducing pipe

Claims (4)

An extraction step of mixing coal particles and a non-hydrogen donating solvent, and extracting the soluble components of the coal into the solvent;
A solvent removal step of removing the solvent from a mixture of the extraction residue and the extract after the extraction step;
A method for producing modified coal, comprising: An extraction step of mixing coal particles and a non-hydrogen donating solvent, and extracting the soluble components of the coal into the solvent;
A solid-liquid separation step for separating the extraction residue and the extract after the extraction step;
A mixing step of mixing a part of the extraction residue separated in the solid-liquid separation step and the extract separated in the solid-liquid separation step;
A solvent removal step of removing the solvent of the mixture after the mixing step;
A method for producing modified coal, comprising: An extraction step of mixing coal particles and a non-hydrogen donating solvent, and extracting the soluble components of the coal into the solvent;
A mixture separation step of extracting a mixture of a part of the extraction residue after the extraction step and the extract;
A solvent removal step of removing the solvent of the mixture;
A method for producing modified coal, comprising:   The manufacturing method of the modified coal for cokes in any one of Claims 1-3.